What does rational resample do for large arrays?

[John Lipor]

I've looked around but can't seem to find documentation on this. Using the Rational Resampling example vi (http://zone.ni.com/devzone/cda/epd/p/id/5784), I have interp set to 1, decimation set to 4, and the sine wave set to 400 samples. When I do this, the output is 100 samples as expected. However, if I kick the sine wave up to 800 samples, the resampled signal is 178 samples. If I turn off anti-aliasing, it's 189 samples. Can someone explain what's goin on here? Thanks!

John

[The_Chancenator]

Hi John,

I'm doing it with just an array of constants, and also get different results.  I believe the best document to shed light on this is the detailed help. At the bottom of the detailed help for the Rational Resample VI, it goes into the details of whats going on with the FIR filter and the various parameters you have described.  Take a look at this, and post back if you've got questions. 

Cheers,